Possible Causes & Corrections
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2003 GMC Sonoma, 2003 GMC Safari, 2003 GMC Jimmy, 2003 Chevrolet S10 Pickup, and 2003 Chevrolet Blazer. However, it is still accessible from the selected car via links, so may be relevant.
Check the following items:
- Inspect ignition system.
- Check for crossfire between spark plugs, such as the distributor cap, spark plug wires, and proper routing of the plug wires.
- Check engine for low compression. Low compression can be caused by improper valve timing, faulty manifold gaskets, sticking or leaking valve. See MECHANICAL INSPECTION under PRELIMINARY INSPECTION & ADJUSTMENTS in BASIC DIAGNOSTIC PROCEDURES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
- Check intake and exhaust system for fresh air entering exhaust upstream of the catalytic converter or restrictions.
- Check fuel system performance. See FUEL SYSTEMS in BASIC DIAGNOSTIC PROCEDURES - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
- Perform fuel injector balance test. See FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.
- Check AIR system for proper operation, if applicable. See DIAGNOSTIC TROUBLE CODE DEFINITIONS in SELF-DIAGNOSTICS - 4.3L ASTRO, BLAZER, JIMMY CANADIAN, SAFARI, SONOMA & S10 PICKUP article.